1. Field of the Invention
The present invention relates to a high power field effect transistor (FET) and method for manufacturing the same.
2. Related Background Art
Because a high power FET needs a high drain breakdown voltage, an FET having the following structure has been proposed. An example is a recessed FET. In such an FET, a recess is formed in a gate region by etching. As a gate electrode is formed in the recess, a source-gate distance is extended and a drain breakdown voltage is enhanced. In order to enhance the drain breakdown voltage, it has also been proposed to space a refractory gate electrode from a drain region ("A New Refractory Self-Aligned Gate Technology for GaAs Microwave Power FET's and MMIC's" IEEE TRANSACTIONS ON ELECTRON DEVICES, vol. 35, No. 5, May 1988).
However, in the prior art FET having the recess structure, since the gate region is recessed by etching, it has been difficult to attain a highly reproducible device characteristic because of reproducibility and controllability of etching.
In the FET disclosed in the above reference, the gate region is of non-etched planar structure but the material of the gate electrode must be a refractory material having heat resistance, and a gate resistance is high. Further, it is difficult to attain a gate electrode of sub half micron such as a gate length of 0.5 .mu.m.